1. Field of the Invention
This invention is directed to a container closure which provides a visual indication that the closure has been opened or tampered with. More particularly, it relates to a tamper evident closure having a tear band which must be torn from both a skirt of the closure and an anchor band permanently secured to a shoulder on the container to which the closure is applied in order to remove the closure from the container.
2. Background Information
There is a growing demand today for container closures, especially for food and medicines, which provide a visual indication if the container has been opened or tampered with in any way. Some of these tamper evident closures include a tear band with prevents removal of the closure until the tear band has been irreversibly severed from the closure cap. In the closure disclosed in U.S. Pat. No. 3,407,957, the tear band is defined by a pair axially spaced annular score lines in an extension of the cylindrical skirt of the closure. The cylindrical section below the tear band is permanently secured to the container neck, and has a flange which extends radially outward further than a pull tab molded to the tear band. Such closures require molds with slides or cams, or post molding operations to form the undercut surfaces and radially extending score lines. This increases the complexity and cost of manufacturing such closures.
There remains a need therefor for a tamper evident closure with provides a clear, reliable indication of previous removal or tampering yet can be produced in a straight draw mold without cams or slides.
There is a further need for such a tamper evident closure which is so distorted in removal that it cannot be replaced without providing an easily recognized indication that it has been removed.
Another difficulty with some tamper evident closures is that they do not provide a clear visual indication of tampering. If the closure is carefully removed and replaced, the fractures cannot be detected without very close scrutiny.